This invention relates to a connector comprising a substrate having a plurality of hybrid electrical circuits, such as LC-filter circuits. The invention relates also to a hybrid substrate for use in such a connector.
A hybrid connector generally comprises a housing having a contact side for making contact to the contact electrodes of a further connector and a connection side for connecting the wiring electrodes of an electrical wiring, such as the wiring tracks on a printed circuit board (PCB). Said housing accommodates a plurality of contact elements or terminals of electrically conducting material extending between said contact and wiring side, supported by an elongated supporting body situated in the housing. At the connection side of the connector a hybrid substrate is provided, having a plurality of hybrid circuits, each comprising a first and second connection electrode, of which the first connection electrode is connected to a contact element of the connector. The second connection electrode generally connects to the signal ground of an electrical device using said connector.
A connector having a hybrid substrate comprising capacitive filter circuits is known, inter alia, from U.S. Pat. No. 4,959,626.
In an embodiment of this U.S. patent, the contact elements are shaped as contact pins which extend from the contact side to the connection side of the connector and provide both on the contact side and the connection side the electrical contact to, respectively, a further connector to be contacted and an electrical wiring to be connected. The filter substrate is provided with through holes in which the contact pins project in their assembled state. Said contact pins and filter circuits i.e. their first connection electrodes, are electrically connected by soldering. It is this manner of connecting the filter circuits and the contact elements of the connector which provides a number of disadvantages.
Solder contacts are per se fairly hard to work and consequently expensive. Account also must be taken of undesirable connections of connection electrodes of the filter components due to the soldering process, unreliable electrical connections as a consequence of contaminants and gas bubbles in the solder joint, etc.
Furthermore, the use of contact pins in combination with a flat hybrid substrate requires the provision of relatively large through holes in the substrate as a consequence of tolerances in the dimensions thereof. In ceramic hybrid substrates used in practice, tolerances in the dimensions of approximately.+-.1% are normal. With a substrate length of, for example, 100 mm, this may lead to a positional tolerance of the through holes of approximately 1 mm. Accordingly, the through holes should then essentially have a cross-sectional size of the pin thickness plus 2 mm. These relatively large holes constitute a lower limit for the pitch distance between the contact elements of the connector, and the area available for the hybrid circuit components on the substrate is limited thereby. In the case of connectors having a large contact element density, the relatively large through holes also have a disadvantageous effect on the mechanical strength and consequently the maximum usable length of the hybrid substrate.